Tip for mechanical pencils



A. WOELM TIP FOR MECHANICAL PENCILS Original Filed Aug. 7, 1926 Patented Aug. 13, 1929. 1

UNITED STATES PATENT OFFICE.

ALFRED 'WOELM, OF BERLIN, GERMANY, ASSIGNOR, BY MESNE ASSIGNMENTS, 'IO PENCIL MECHANISM CORPORATION, A CORPORATION OF NEW YORK.-

TI]? FOR MECHANICAL PENCILS.

Application filed August 7, 1926, Serial No. 127,850. Renewed January 11, 1929.

My invention relates to mechanical pencils, particularly to that part thereof through which the lead is projected and which supports and guides the writing end thereof, and is called the tip. 'Such tips being also used to some extent on holders for pencil leads and crayons.

The tips which are most generally used on mechanical pencils are conical shaped, have a bore central therethrough, and the small end thereof is split to form a number of more orless springy fingers. The diameter of the bore through the fingered end is generally somewhat less than the average diameter of the leads which are to be handled, so that the fingers will have a tendency to prevent free passage of the lead through the tip by maintaining a braking tension thereon at all times, the object being to prevent the leads from dropping through the tip when released. by the lead holding mechanism of the pencil.

The form of the tips is such that the fingers, each of which is an arc of a circle, and is increasingly thick toward its inner end, are but limitedly resilient, while the variation in the diameter of the leads renders it im aractical to reduce the diameter of the bore t rough th fingered end by more than a very limited amount, for when a greater reduction is made when an over size lead is encountered the tip will become jammed and the pencil cease to function properly.

The invention will be best understood by reference to the accompanying drawing in which the figure represents the preferred form of pencil tip half in elevation and half in longitudinal section.

In the form here illustrated the base of the conical tip 2, is turned down and threaded to form shank or stem 3, but another form of tip is provided with an internal thread.

The borethrough the tip is preferably stepped down somewhat as illustrated, but the lower end thereof may be tapered if so desired. The small end of the tip portion is then split by a saw cut or cuts 4 into a number of fingers. In so far as above described it is the usual tip, the fingers Whereofare but slightly springy, the available resilienc being restricted to the free ends of the gers.

In order to increase the resiliency of the fingers, I remove a portion of the metal near their base by forming a groove or grooves 5, thereby so reducing their cross section that they Will yield resiliently at that point, as well as at their thin end, under such force as would normally be available to force an over size lead through the tip, and the maximum whereof is preferably less than that required to cause fracture of the lead. The forming of these grooves will tend to force the free ends of the fingers toward each other so that the resiliency of the metal from which they are formed may be utilized to hold an undersized lead.

It will be apparent that in addition to the above described practical means of improving the action and characteristics of the tip, the principle of adding one or more planes of elasticity, may be carried out by the use of several modifications of grooves, slots, perforations and the like running in the above described or other directions. It is accordingly understood thatl reserve the privilege of resorting to the embodiment of the essential features or principles of my present improvements in numerous other structural modifications as may fairly be comprehended within the spirit and scope of the appended claims.

1 claim:

1. A tip for mechanical pencils, comprising a member in the form of a truncated coneand having a longitudinal bore therethrough, said member being formed with an annular slot adjacent the base thereof and extending more than half the distance from the outer conical surface of the member to said bore, and with a plurality of longitudinal slots extending from said annular slot to the end of the tip, whereby to provide a plurality of resilient fingers.

2. A tip for mechanical pencils, comprising a member in the form of a truncated cone and having a longitudinal bore therethrough, said bore having a uniform diameter of relatively small extent throughout the portion thereof adjacent the feeding end of the tip and having a uniform diameter of relatively greater extent throughout the rest of its length, said member being formed with an annular slot adjacent the base thereof and extending more than half the distance from the outer conical surface of the member to said bore, and with a plurality of longitudinal slots extending from said annular slot to the end of the tip, whereby to provide a plurality of resilient fingers.

3. A tip for mechanical pencils, comprising a member having a longitudinal bore therethrough and providing at one end a mouth through which leads may be ejected, said member being formed with a plurality of longitudinal slits extending rearwardly from said mouth and being laterally recessed at both sides of each slit at a point to the rear of said mouth, the recesses thus provided extending to a depth at least onehalf the distance between the outer surface of the member and said bore.

4. A device adapted to provide a tip for mechanical pencils, comprisng an attaching member'at its upper end, and a tip member, and having a lonigtudinal bore therethrough, said tip member being formed with a plurality of slits extending upwardly from its lower end to provide a plurailty of leadgripping fingers and being laterally recessed at both sides of each slit at a point adjacent the upper end of said tip member,

the lower portion thereof and having a 1 diameter of relatively greater extent throughout the rest of its length, said tip member being formed with aplurality of slits extending upwardly from its lower end to provide a plurality of lead-gripping fingers and being laterally recessed at both sides of each slit at a point adjacent the upper end of said tip member, the recesses thus provided extending to a depth at least one-half the distance between the outer surface of said tip member and said bore.

In testimony whereof I affix my signature.

' ALFRED WOELM.

' CERTIFICATE, or CORRECTION.

' Patent No. 1,724,245.

I Granted August 13, 1929, to

ALFRED WonLM.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 1, line 48, strike .out the words "tip portion" and insert instead "conical tip"; and that the said Letters Patent should be read with this correction therein that the same may conform to ,the record of the 'case in the Patent Office.

Signed and sealed this 15th day of October, A. D. 1929.

I (Seal) M. J. Moore, Acting Commissioner of Patents. 

